html {

    font-size: calc(100vw/750*100);
  }
  
  body {
    font-size: .14rem;
  }
  
  html,
  body {
    width: 100%;
    height: 100%;
  }

  .box{
      width: 100%;
      height: 100%;
      display: flex;
      flex-direction: column;
      header{
          width: 100%;
          height: 1rem;
          border-bottom: 1px solid #000;
          display: flex;
          .spone{
              font-size: .4rem;
              line-height: 1rem;
              margin-left: .2rem;
          }
          .sptwo{
            font-size: .4rem;
            line-height: 1rem;
            margin-left: 2.5rem;
          }
      }
      nav{
          width: 100%;
          height: .7rem;
          border-bottom: 1px solid #999;
      }
      main{
          flex: 1;
          overflow: auto;
      }
  }